refactor: consolidate app configurations and utility scripts

- Move 32+ app-specific scripts from features/apps/scripts/ to features/scripts/utils/ for centralized packaging.
- Create individual Nix modules for orphaned app configurations (btop, kitty, tmux, etc.) in features/apps/ using xdg.configFile.
- Fix broken paths in core/system/makima.nix and features/apps/vscode.nix.
- Update VSCode configuration to use the modern 'profiles.default.userSettings' API, resolving deprecation warnings.
- Merge duplicate 'nomarchy-launch-walker' scripts into a single robust utility.
- Remove stale root 'config/' directory.
- Update README.md and docs/creating-themes.md to reflect the new architecture and keybindings.
- Ensure all modules are correctly imported and verified via nix flake check.

core/system/browser.nix

@@ -0,0 +1,30 @@
+{ config, pkgs, lib, ... }:
+
+let
+  nomarchyLib = import ../../lib { inherit lib; };
+  activeThemeName = config.nomarchy.system.theme;
+  currentPalette = nomarchyLib.getPalette activeThemeName;
+
+  # Hex color for browser theme (base00 is background)
+  themeColor = "#${currentPalette.base00}";
+
+  # Detect light mode from theme name or palette
+  isLightTheme = nomarchyLib.isThemeLightMode {
+    themeName = activeThemeName;
+    assetsPath = ../../themes/palettes;
+  };
+
+  browserPolicy = {
+    BrowserThemeColor = themeColor;
+    BrowserColorScheme = if isLightTheme then "light" else "dark";
+  };
+in
+{
+  # Chromium policies
+  programs.chromium.extraOpts = lib.mkDefault browserPolicy;
+
+  # Brave browser policies via managed policy file
+  environment.etc."brave/policies/managed/nomarchy.json".text = lib.mkDefault (
+    builtins.toJSON browserPolicy
+  );
+}